Impact fuzes with mechanical retardation



March 4, 1958 G. KUHN 2,825,284

IMPACT FUZES WITH MECHANICAL RETARDATION Filed Sept. 7, 1955 2Sheets-Sheet 1 H C r f "a 5b k 7 18b INVENTOR Georges Kulzrc.

ATTO ENE Y IMPACT FUZES WITH MECHANICAL RETARDATION Georges Kuhn,Geneva, Switzerland, assignor to Mefina S. A., Fribourg, Switzerland, acorporation of Switzerland Application September 7, 1955, Serial No.532,029

Claims priority, application Switzerland November 5, 1954 1 Claim. (Cl.102-71) nited States Patent-"O Patented Mar. 4, 1958 walls 11a securedto the body C and acting on an axially movable body 10, against theaction of a spring 12. In the normal position, said device is secured inthe known manner by centrifugal locking members 9, located, forconvenience of the drawing, in the plane of the section of Fig. 1.

The upper end of the rod 8 is located in the path of I the rod of thepusher 13 located in the head of the body z i the striker 5.

Said fuzes are not very sensitive and have no C, in the known manner,and adapted to be moved towards the interior of the said body on impact.

The other end of the rod 8 comprises a stop 8b which in the normalposition is located opposite the bolt 7 of The operation of said fuze isas follows:

During. the firing of the shot, and when the axial acceleration ceases,the auto-destruction device, formed by the balls 11, the inclinedsurfaces 11a and the body 10, produces, under the action of centrifugalforce, the compression of the spring 12 of the rod 8 and, at the sametime, the locking "members of said rod move radially and release theshoulder 8a.

From this moment, the fuze can operate, either on impact, 'or by reasonof the operation of the autotype of. fuze the retardation on impact isobtained by pyro-technical means which, however, are difiicult to storeand operate in a very irregular manner, causing much longer periods ofretardation or do not even provide it at all. i

The present invention has for its subject a sensitive fuze operating onimpact with a mechanical delay and of which the striker is subjected tothe action of a spring.

It is characterised in that its striker is held in the cocked positionby a bolt, itself held in the locked position by a movable membercontrolled at least by a member actuated on impact.

One form of construction of the subject of the invention is showndiagrammatically and by way of example in the accompanying drawings,wherein:

Fig. 1 is an axial section.

Figs. 2 and 3 are cross-sections to a larger scale on the line IIII ofFig. 1 in the normal position and in the cocked position.

The fuze has a body C in which is located the main charge 1 of thedetonator, with a relay 2 adapted to transmit to said charge the actionof the combined percussion cap 3. The latter is mounted on anoscillating member 4 pivoted eccentrically at 4a. Said member comprisesa toothed sector 4b gearing with a pinion 40 forming part of the rockerrelease mechanism 4d. This assembly forms a safety device for thedetonator, as in the normal position, the percussion cap 3 is withdrawnfrom the path of the striker 5 and from the relay 2. It can only bemoved opposite these members, after firing the projectile, under theaction of centrifugal force.

The striker 5 is formed by a sliding rod subjected to the action of aspring 6, which at one end bears against a shoulder 5c of the body ofthe fuze and, on the other end, against a shoulder 5a of the rod 5,provided with a conical surface 5b. The striker is located eccentricallyin the body C and parallel to the axis of the latter.

The conical part 5b of the striker is in contact with a bolt 7, with arounded end 7a, and which slides in a radial bore located in a planeperpendicular to the axis of the body C.

Along the axis of the body C is located a sliding rod 8,

which is provided with a shoulder 8a subjected to the destruction deviceprovided the safety device of the detonator has reached its activeposition.

In the first case, when the point of the fuze contacts an object, thepusher 13 is pushed towards the interior and its rod comes into contactwith the upper end of the rod 8, which is thus moved axially.

This axial movement of the rod 8 moves the stop 86 so that the bolt 7 isreleased. The spring 6 acting on the striker then repels, by the conicalpart 5b in contact with the rounded part 7a the bolt 7 inwardly, and thestriker is moved axially in the direction of the relay 2.

When the safety device of the detonator, formed by the oscillatingmember 4 carrying the percussion cap 3, which is set in operation, onfiring the shot, in the known manner, has had time to function and thepercussion cap 3 is opposite the striker, position shown in Fig. 3, theper- ,cussion cap is contacted and fires the charge 1 by means of therelay 2.

When the striker is released before the sector 4 has reached theposition shown'in Fig. 3, it contacts a solid part of said sector. Theprojectile cannot explode.

If the projectile on which the foregoing described fuze is mounted doesnot strike the desired target, here an airplane, the explosion must becaused by the auto-destruction means including the axially movable body10, the balls 11, and the spring 12 operating in the following manner:

When the gyratory movement of the projectile diminishes, the centrifugalforce acting on the balls 11 also diminishes thereby causing the spring12 to push the axially movable body 10 towards the main charge 1. Theaxially movable body 10 then contacts the shoulder 81: of the slidablerod 8 thereby causing the rod 8 to slide downwardly. Thestop 8a is thusdisplaced downwardly thereby freeing the bolt 7 thereby allowing thespring 6 to cause the downward movement of the striker 5. The striker 5then penetrates the percussion cap 3, which has been brought into thepath of striker S by the oscillating member 4, thus causing thedestruction of the projectile before it falls to the ground.

It will be understood that'modifications may be made in the details ofconstruction without departing from the scope of the invention. Thus thefuze need not comprise an auto-destruction device, or the safety devicefor the detonator and for the trajectory for maintaining percussion cap3 out of reach of the striker 5, until the end of the safety path oftravel of the trajectory.

The pusher 13 may form part of the rod 8.

Variations in the. retardation of the; release ofthe striker may beobtained by selection of the strength of its spring 6, the conicity ofits part 5b and the size of its bolt 7.

I claim:

A sensitive fuze for a projectile having a projectile charge,comprising, in combination, a fuze body having an axis, a pusher memberpositioned in said body at its head portion and along said axis, anaxially slidable ramming rod positioned in said body oppositely to saidpusher rod at its upper end and alongsaid axis of said fuze body, saidramming rod having a shoulder portion intermediate its ends and a stopmember at its lower end, centrifugal locking members positioned aboutsaid ramming rod about the portion thereof intermediate said shoulderportion and said stop member, said locking members abutting saidshoulder portion of said ramming rod, an axially movable body positionedabout said ramming rod at the portion thereof having said shoulderportion, first spring means positioned about said ramming rod forholding said axially movable body in position, ball means for causingsaid axially movable body to move downwardly against said spring means,a striker rod having a striking end, said striker rod being positionedin said fuze body and being parallel and eccentrically mounted withrespect to said slidably mounted ramming rod, said striker rod having aconical surfaced shoulder portion intermediate its ends, one of saidends being a striking end, a projectile charge positioned in said bodyat its lower portion opposite to its head portion, a member mounted foroscillation on a plane perpendicular to the plane of the axis of saidbody, said member being eccentrically mounted with respect to the axisof said fuze body and to said striker rod and being positioned betweenthe striking end of the striker rod and the projectile charge, apercussion cap mounted on said memher mounted for oscillation, secondspring means positioned about said striker rod intermediate said conicalsurfaced shoulder portion and the end of said striker rod opposite tothe striking end for urging said striker rod towards said projectilecharge, said fuze body having a radial bore therein and positionedbeneath said centrifugal locking members on a plane perpendicular to theplane of said axis of said fuze body, a bolt positioned in said bore,said bolt being in contact both with said stop member of said rammingrod and with said conical surfaced shoulder portion of said striker rod,whereby the fuze will be mechanically retarded in its functioning onimpact with a target offering small resistance and whereby, upon thefailure of the projectile to hit the target and upon the diminishing ofthe gyratory movement of the projectile with the accompanyingdiminishing of the centrifugal force acting on said ball means, saidfirst spring means is caused to urge said axially movable body towardsthe projectile charge and said axially movable body contacts saidshoulder portion of said ramming rod thereby causing said ramming rod tomove towards said projectile charge and thereby causing said stop memberof said ramming rod to be displaced downwardly to allow said secondspring means to urge said conical surfaced shoulder portion to move saidbolt radially and to urge said striker rod downwardly towards saidprojectile charge to cause the detonation of said charge before theprojectile reaches the ground.

References Cited in the file of this patent UNITED STATES PATENTS1,523,073 Junghans Jan. 31, 1925 2,149,469 Schenk Mar. 7, 1939 2,701,527Granath Feb. 8, 1955 2,718,850 Kuhn Sept. 27, 1955

